* [feign] add threetenbp support for feign clients
* [okhttp] add threetenbp support for okhttp clients
* [jersey] add threetenbp support for jersey clients
* [retrofit2] add threetenbp support for retrofit2 clients
* [spring] add threetenbp support for spring generators
* add a workaround in tests for a bug in the petstore
The petstore doesn't manage fractional digits of dates correctly when there are less than 3
